This was funnier when it didn't need so much explaining, but here goes anyway. DH is a real estate appraiser. Appraisers generate reports about the subject property and the nearby comparable sales, or "comps." On one page of the report, there is a map with arrows pointing at "Subject," "Comp 1," "Comp 2" and so on. These days you click and drag them on a screen, of course, but at the time they were still doing paper reports. You rubbed the little arrows on from a transfer sheet.
So anyway, there was a postcard on the bulletin board with Heathcliff the cat next to a huge stone lion, with the caption "Dream Big!" It didn't take long before someone had added a "Comp 1" arrow pointing at Heathcliff.